1. Technical Field
The present invention relates to electro-optical devices, methods for manufacturing such electro-optical devices, and electronic apparatuses. The present invention particularly relates to an electro-optical device including a color filter including color layers of additive primary colors, a method for manufacturing such an electro-optical device, an electronic apparatus including such an electro-optical device.
2. Related Art
Liquid crystal displays are examples of known electro-optical devices for displaying images. The liquid crystal displays each include a plurality of subpixel regions opposed to electrodes. In the liquid crystal displays, light passing through liquid crystal materials present in the subpixel regions is modulated in such a manner that the subpixel regions are turned on or off by selectively applying voltages to the electrodes, whereby pictures or characters are displayed.
The liquid crystal displays include color filters for coloring light so as to display color images. The color filters include color layers of the three additive primary colors: red (R), green (G), and blue (B). Various colors are reproduced by controlling the magnitude of the voltage applied to each subpixel region or controlling the balance between the three additive primary colors.
The color filters include the color layers of the three additive primary colors as described above. Since a desired color depends on functions or uses of the liquid crystal displays, color resists for forming the color layers need to be prepared for each function or use thereof.
For a transflective liquid crystal display for displaying an image in a reflective or transflective mode, in order to eliminate the difference in brightness between light beams that pass through color layers disposed in reflective or transmissive regions having different optical path lengths, different color resists are used to form subpixel regions of the same color in some cases.
JP-A-2005-25002 (hereinafter referred to as Patent Document 1) discloses a color liquid crystal display that includes a minimized number of color filters for the sake of reducing costs such as development cost. The color liquid crystal display includes pixels that each have a reflective section including a reflective layer and also each have a transmissive section including no reflective layer. The pixels correspond to a plurality of primary colors. With reference to FIGS. 22A, 22B, and 22C, some of the pixels that correspond to at least one of the primary colors each have a dark color filter portion A covering a portion of the reflective section and a portion of the transmissive section and also each have a light color filter portion B covering a remaining portion of the reflective section and a remaining portion of the transmissive section.
In the color liquid crystal display described in Patent Document 1, a deep color filter and a light color filter are used for one of the primary colors; hence, at least four color resists need to be prepared. If dark color filters and light color filters are used for all of the primary colors, at least six color resists need to be prepared. The number of kinds of color resists that need to be prepared is greater than the number of the primary colors. Therefore, the color liquid crystal display is disadvantageous in cost. An increase in the number of kinds of color resists increases the number of steps of forming the color layers. This leads to a reduction in manufacturing efficiency.
In the color liquid crystal display, the color of each subpixel region cannot be varied although the reflective section and the transmissive section can be varied in color density; hence, the reflective section and the transmissive section cannot be individually adjusted to a desired color.